1. Field of the Invention
The present invention relates generally to video and, more specifically, to image enhancement.
2. Description of the Related Art
Images in video conference calls may suffer from exposure and/or white balance problems. Exposure problems may be caused by too much or too little light being received through the camera. White balance problems may be caused by incorrect ratios of colors in the image. Correct exposure may be more difficult to achieve than white balance, because white balance may be easier to fix than exposure after the image is acquired.
Gray world algorithms and specular reflection algorithms are two categories of white balance algorithms. Gray world algorithms may look for approximately the same amount of color in Red Green Blue (RGB) space (or equal Cb and Cr in YCC space) and adjust for any offsets. In YCC space, Y is a measure of luminance (intensity of light per unit area), Cb is a measure of blue chrominance (luminance minus blue), and Cr is a measure of red chrominance (luminance minus red). Specular reflection models may assume that the brightest spots in an image reflect the light source neutrally and may adjust the spectrum of the image accordingly. Both gray world algorithms and specular reflection models have disadvantages that may result in poor image quality.